I find Firebirds really comfortable to play, once you've got them balanced. That's their main problem. On the Firebirds I've had I've had to move both strap buttons to the back of the guitar, one right on the neck joint and one on the upper... arm.. rest... bit. Whatever that's called. It ends up looking damn silly but it's the only way to get the buggers to balance right, even then they still dive a bit. I noticed Warmoth started making chambered Firebird bodies - seems like the worst idea in the world to me, that's just going to make it even more impossible to get sitting comfortably.
Anyhoo, only thing I can comment on really is the headstock - from what I can tell the Warmoth headstock is actually very close tot he modern headstocks Gibson and Epiphone are using on Firebirds. Again, why they deemed it necessary to enlarge the headstock of an already atrociously balanced guitar, I have no idea. But Warmoth's does look like it matches the newer style, anyway. There's been much talk (read: complaining) about this within the (albeit very small) Gibson Firebird enthusiast circles, that both the Gibson headstock has increased a little and the Epiphone headstock has increased a lot both in outline and thickness.
Plus there probably is the issue of licensing.
